Install a Green Roof

When to Start: Spring
At Its Best: All year round
Time to Complete: 2-3 hours, or longer, depending on roof size

Materials Needed:

• heavy-duty plastic sheet, such as butyl pond-liner
• sand or gravel, or custom-made underlay
• sedum matting

• sharp knife
• slow-release granular fertilizer

Assess Your Roof

If you want to cover a roof on your house, it is best to consult an expert first to ensure that the proposed area can take the weight of the planting and growing medium, and that it has sufficient drainage. Green roof specialists can be found on the internet or in local directories.

First Steps

For flat or gently sloping shed roofs or similar garden structures, sedum matting is the best option for because it is easy to lay and maintain. Sedum mats come complete with mature plants already established on a special material and in growing medium, and should be laid soon after delivery. The matting is heavy, especially when wet, and will require two people to lift it onto the roof.

Install an Underlay

First, lay a heavy-duty plastic sheet, such as a pond-liner, over the roof to create a waterproof root barrier, then add a layer of sand or gravel, or a custom-made underlay sold by the suppliers. Ensure that the surface is even to prevent puddling when it rains since the plants do not tolerate waterlogging.